COMMUNICATIONS
anionic intermediate A to C4F9I, N-radical intermediate
B, perfluobutyl radical, and iodide ion are generated.
We tried to capture the intermediate B by adding
styrene, however no aimed product was obtained
maybe because of the high reactivity of intramolecular
reaction. Subsequently, N-radical intermediate B is
oxidized by C4F9I to give intermediate C. Meanwhile,
the perfluorobutyl radical may abstract one hydrogen
from the starting material 1a to give the intermediate
B and release the perfluorobutane as gas. Then, the
C=C bond of styrene may be activated by the
iodonium ion to form the iodonium intermediate D,
and the subsequent intramolecular nucleophilic addi-
tion with a nitrogen anion generates the iodo-isoindoli-
none intermediate E which then released one HI to
yield product 2a.[12]
Scheme 3. Reaction applications: a. Pd-catalyzed Heck annula-
tion for the synthesis of tetracyclic isoindolinone derivative. b.
A gram-scale reaction.
In summary, a simple and concise method was
developed to synthesize isoindolinones through the
intramolecular amidation of ortho-vinyl benzamides. A
variety of N-aryl isoindolinone derivatives with good
The UV-vis spectroscopic measurement on various yields were acquired through this approach. Perfluor-
combinations of 1a, C4F9I and Cs2CO3 in DMF was obutyl iodide was proved to be necessary and used as
offered. We observed a red shift of absorption when the unique oxidant.
substrate 1a, C4F9I and Cs2CO3 were combined in
DMF, which indicates the formation of EDA complex
(see SI for details).
Experimental Section
On the basis of our experimental results and a General Procedure of Intramolecular Amidation
previous reported work,[9,11] we proposed a tentative
A
solution of N-phenyl-2-vinylbenzamide 1a (44.7 mg,
reaction mechanism of the intramolecular amidation of
ortho-vinyl benzamides (Scheme 4). Under a base
condition, the deprotonation of substrate 1a firstly
produces the anionic intermediate A. Then an EDA
complex could form between N-anionic intermediate A
0.2 mmol), Cs2CO3 (130 mg, 0.4 mmol), and C4F9I (69 μL,
0.4 mmol) in DMF (1 mL) was stirred at room temperature for
12 h. After the completion of the reaction, the mixture was
diluted with EtOAc (15 mL) and water (15 mL). The organic
layer was separated, and the aqueous layer was extracted with
and C4F9I. Through the single electron transfer from N- EtOAc (15 mL×3). The combined organic layers were dried
over Na2SO4, filtered, and concentrated in vacuo. Then, the
crude product was purified through flash chromatography to
produce 3-methylene-2-phenylisoindolin-1-one 2a as a pale-
yellow solid (43 mg, 97% yield). M. p. 175.0–176.5 C. 1H
°
NMR (400 MHz, CDCl3) δ 7.83 (d, J=7.5 Hz, 1H), 7.66 (d,
J=7.7 Hz, 1H), 7.54 (t, J=7.5 Hz, 1H), 7.49–7.39 (m, 3H),
7.34–7.26 (m, 3H), 5.13 (d, J=2.0 Hz, 1H), 4.71 (d, J=2.0 Hz,
1H). 13C NMR (100 MHz, CDCl3) δ 166.69, 143.13, 136.28,
134.62, 132.35, 129.79, 129.38, 128.95, 128.15, 128.07, 123.58,
120.11, 90.50. HRMS (ESI) calculated for C15H11NONa (M+
Na)+: 244.0733, found: 244.0737.
Acknowledgements
This work was supported by the National Science Foundation of
China (21702236, 21772240), the Doctor Initiated Project of
Guangdong Natural Science Foundation (2016A030310459),
and Guangzhou Science Technology and Innovation Commis-
sion Technology Research Projects (201805010005).
Scheme 4. Proposed mechanism
Adv. Synth. Catal. 2020, 362, 1–6
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